net.sourceforge.cilib.coevolution.cooperative.problemdistribution.RandomAlgorithmImperfectSplitDistribution Maven / Gradle / Ivy
/** __ __
* _____ _/ /_/ /_ Computational Intelligence Library (CIlib)
* / ___/ / / / __ \ (c) CIRG @ UP
* / /__/ / / / /_/ / http://cilib.net
* \___/_/_/_/_.___/
*/
package net.sourceforge.cilib.coevolution.cooperative.problemdistribution;
import com.google.common.base.Preconditions;
import java.util.List;
import net.sourceforge.cilib.algorithm.Algorithm;
import net.sourceforge.cilib.algorithm.iterator.RandomAlgorithmIterator;
import net.sourceforge.cilib.algorithm.population.SinglePopulationBasedAlgorithm;
import net.sourceforge.cilib.coevolution.cooperative.CooperativeCoevolutionAlgorithm;
import net.sourceforge.cilib.coevolution.cooperative.problem.CooperativeCoevolutionProblemAdapter;
import net.sourceforge.cilib.coevolution.cooperative.problem.DimensionAllocation;
import net.sourceforge.cilib.coevolution.cooperative.problem.SequentialDimensionAllocation;
import net.sourceforge.cilib.problem.Problem;
import net.sourceforge.cilib.type.types.container.Vector;
/**
* This {@linkplain ProblemDistributionStrategy} performs a split by assigning a
* sequential portion of the varying length to each participating
* {@linkplain PopulationBasedAlgorithm}.
*
* Defaults into a split of equal sizes if possible. The order in which the
* algorithms are assigned is generated randomly.
*/
public class RandomAlgorithmImperfectSplitDistribution implements
ProblemDistributionStrategy {
/**
* Splits up the given {@link Problem} into
* sub-problems, where each sub problem contains a sequential
* non-uniform sized) portion of the problem vector, and assigns them to all
* the participating {@link Algorithm}s. This implementation assigns a
* portion of length dimensionality/number of populations + 1 to
* dimensionality % number of populations of the participating populations.
* The order in which the algorithms are assigned is generated randomly.
*
* @param populations The list of participating
* {@linkplain PopulationBasedAlgorithm}s.
* @param problem The problem that needs to be re-distributed.
* @param context The context vector maintained by the
* {@linkplain CooperativeCoevolutionAlgorithm}.
*/
public void performDistribution(List populations,
Problem problem, Vector context) {
Preconditions.checkArgument(populations.size() >= 2,
"There should at least be two Cooperating populations in a Cooperative Algorithm");
int dimension = problem.getDomain().getDimension() / populations.size();
int oddDimensions = problem.getDomain().getDimension() % populations.size();
int i = 0;
int offset = 0;
RandomAlgorithmIterator iterator = new RandomAlgorithmIterator<>(populations);
while (iterator.hasNext()) {
int actualDimension = dimension;
if (i < oddDimensions) {
actualDimension++;
}
DimensionAllocation problemAllocation = new SequentialDimensionAllocation(offset, actualDimension);
iterator.next().setOptimisationProblem(new CooperativeCoevolutionProblemAdapter(problem, problemAllocation, context));
offset += actualDimension;
++i;
}
}
}